1. Field of the Invention
This invention relates to an apparatus for conserving battery power and, more particularly, to an apparatus for controlling a ringer on a cordless telephone.
2. Background
A typical cordless telephone, such as the one disclosed in U.S. Pat. No. 4,992,720 issued to Hata, is comprised of a base unit and a portable handset which both have antennas and transceivers for communicating with each other. When the handset is removed from the base unit, a battery in the handset powers the transceiver and other electronics in the handset to allow the portable operation of the telephone. The description of the cordless telephone in U.S. Pat. No. 4,992,720 is hereby incorporated by reference.
The battery on the handset has a limited charge and must be periodically recharged by returning the handset to the base unit. The base unit detects the battery in the handset and begins a trickle charge operation which takes an amount of time which varies according to the strength of the battery.
The primary benefit of the cordless phone is that the handset need not be at a fixed location and need not be located close to the base unit. As a result, the handset is commonly away from the base unit and is not returned to the base unit for recharging as often as necessary. Consequently, the battery in the handset may not be at full strength and the length of time that the handset is operable is therefore limited.
When an incoming call is received over a telephone line, the base unit signals the handset of the incoming call and the handset operates a ringer. The operation of the ringer at the handset substantially reduces the life of the battery. In a household with more than one telephone, the ringer for each telephone in the household will be activated by the incoming call. Because of the other telephones, the operation of the ringer on the handset may not be necessary to inform the resident of the incoming call.
Many cordless telephones have a ringer switch which enables a user to simply turn on or off the ringer at his or her convenience. Some people, however, may not know about the ringer switch or may not know the value of turning the ringer off with the switch. Furthermore, many people do not want to bother with switching the ringer on and off, especially since they may forget that the ringer has been switched off when they actually want the ringer active. A need therefore exists for a cordless telephone that conserves battery power by deactivating the ringer when the ringer is not necessary.